Apparatuses and systems for acoustic channel auto-balancing during multi-channel signal extraction

• US 10,339,952 B2
• Filed: 10/14/2017
• Issued: 07/02/2019
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: Solos Technology Limited
• Original Assignee: Kopin Corporation
• Inventors: Fan, Dashen
• Primary Examiner(s): Augustin, Marcellus J
• Application Number:
  US15/784,102
• Publication Number:
  US 20180040334A1
• Time in Patent Office: 626 Days
• Field of Search: 704 2- 8, 704200-274
• CPC Class Codes: G10K 11/002 Devices for damping, suppressing, obstructing or conducting sound in acoustic devices G10K1/06 - G10K1/10 take precedence; for electro-mechanical transducers for communication H04R3/002
• CPC Class Codes: G10K 2210/3015 Averaging, e.g. exponential
• CPC Class Codes: G10K 2210/3028 Filtering, e.g. Kalman filters or special analogue or digital filters
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: G10L 2025/783 based on threshold decision
• CPC Class Codes: G10L 21/02 Speech enhancement, e.g. noise reduction or echo cancellation reducing echo effects in line transmission systems H04B3/20; echo suppression in hands-free telephones H04M9/08
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain
• CPC Class Codes: G10L 25/84 for discriminating voice from noise
• CPC Class Codes: H03G 3/00 Gain control in amplifiers or frequency changers
• CPC Class Codes: H03G 7/002 in untuned or low-frequency amplifiers, e.g. audio amplifiers H03G7/007, H03G7/001, H03G7/008, H03G7/02, H03G7/06 take precedence
• CPC Class Codes: H03G 7/007 of digital or coded signals
• CPC Class Codes: H04R 2410/05 Noise reduction with a separate noise microphone
• CPC Class Codes: H04R 2460/01 Hearing devices using active noise cancellation
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Systems and apparatuses are described to automatically balance acoustic channel sensitivity. A computer readable medium containing executable computer program instructions, which when executed by an acoustic signal processing system, cause the acoustic signal processing system to perform a process that includes calculating a long-term power level of a main acoustic signal to obtain an averaged main acoustic signal. Segments of the main acoustic signal are excluded from the averaged main acoustic signal using a desired voice activity detection signal. A long-term power level of a reference acoustic signal is calculated to obtain an averaged reference acoustic signal. Segments of the reference acoustic signal are excluded from the averaged reference acoustic signal using the desired voice activity detection signal. An amplitude correction signal is created using the averaged main acoustic signal and the averaged reference acoustic signal. The amplitude correction signal is used to adjust either the main acoustic signal or the reference acoustic signal to automatically balance acoustic channel sensitivity.

Claims

1. A non-transitory computer readable medium containing executable computer program instructions, which when executed by an acoustic signal processing system, cause the acoustic signal processing system to perform a process comprising:

calculating a long-term power level of a main acoustic signal to obtain an averaged main acoustic signal, wherein segments of the main acoustic signal are excluded from the averaged main acoustic signal using a desired voice activity detection signal;

calculating a long-term power level of a reference acoustic signal to obtain an averaged reference acoustic signal wherein segments of the reference acoustic signal are excluded from the averaged reference acoustic signal using the desired voice activity detection signal; and

creating an amplitude correction signal using the averaged main acoustic signal and the averaged reference acoustic signal, wherein the amplitude correction signal is used, to adjust either the main acoustic signal or the reference acoustic signal to automatically balance acoustic channel sensitivity.

2. The computer readable medium of claim 1, wherein excluded segments of the main acoustic signal contain desired audio, and excluded segments of the reference acoustic signal contain desired audio.

3. The computer readable medium of claim 1, wherein the creating normalizes the averaged main acoustic signal by the averaged reference acoustic signal and the process further comprising:

correcting the reference acoustic signal with the amplitude correction signal.

4. The computer readable medium of claim 3, wherein the correcting multiplies the amplitude correction signal by the reference signal.

5. The computer readable medium of claim 1, wherein the creating normalizes the averaged reference acoustic signal by the averaged main acoustic signal and the process further comprising:

correcting the main acoustic signal with the amplitude correction signal.

6. The computer readable medium of claim 5, wherein the correcting multiplies the amplitude correction signal by the main acoustic signal.

7. The computer readable medium of claim 1, the process further comprising:

filtering the main acoustic signal with a voice band filter before the calculating the long-term power level of the main acoustic signal; and

filtering the reference acoustic signal with a voice band filter before the calculating the long-term power level of the reference acoustic signal.

8. The computer readable medium of claim 1, the process further comprising:

calculating a long-term power level of a second reference acoustic signal to obtain an averaged second reference acoustic signal, wherein segments of the second reference acoustic signal are excluded from the averaged second reference acoustic signal using the desired voice activity detection signal; and

creating a second amplitude correction signal using the averaged main acoustic signal and the averaged second reference acoustic signal.

9. The computer readable medium of claim 8, wherein the creating the second amplitude correction signal normalizes the averaged main acoustic signal by the averaged second reference acoustic signal and the process further comprising:

correcting the second reference acoustic signal with the second amplitude correction signal.

10. The computer readable medium of claim 9, wherein the correcting multiplies the second amplitude correction signal by the second reference acoustic signal.

11. The computer readable medium of claim 1, wherein a duration of an averaging time ranges from a fraction of a second to minutes.

12. An integrated circuit device to automatically balance acoustic channel sensitivity, comprising:

a first signal path, the first signal path is configured to receive and average acoustic signals from a first microphone channel to produce a long-term running average power level of the first microphone channel, exclusive of segments containing desired audio;

a second signal path, the second signal path is configured to receive and average acoustic signals from a second microphone channel to produce a long-term running average power level of the second microphone channel, exclusive of segments containing desired audio;

a first normalizer, the first signal path is coupled to a first input into the first normalizer and the second signal path is coupled to a second input into the first normalizer, the first normalizer is configured to normalize a signal on the first input by a signal on the second input to output an amplitude correction signal; and

a first multiplier, the first multiplier is coupled to the second signal path and to an output of the first normalizer, the first multiplier is configured to multiply the amplitude correction signal by acoustic signals on the second microphone channel to produce a corrected second microphone signal.

13. The integrated circuit device of claim 12 further comprising:

a first voice band filter, the first voice band filter is part of the first signal path and acoustic signals from the first microphone channel are filtered before the long-term running average power level is calculated; and

a second voice band filter, the second voice band filter is part of the second signal path and acoustic signals from the second microphone channel are filtered before the long-term running average power level is calculated.

14. The integrated circuit device of claim 12, wherein a long-term running average is performed over an interval that can range from a fraction of a second to minutes.

15. The integrated circuit device of claim 12, further comprising:

a third signal path, the third signal path is configured to receive and average acoustic signals from a third microphone channel to produce a long-term running average power level of the third microphone channel, exclusive of segments containing desired audio;

a second normalizer, the first signal path is coupled to a first input into the second normalizer and the third signal path is coupled to a second input into the second normalizer, the second normalizer is configured to normalize a signal on the first input by a signal on the second input to output a second amplitude correction signal; and

a second multiplier, the second multiplier is coupled to the third signal path and to an output of the second normalizer, the second multiplier is configured to multiply the second amplitude correction signal by acoustic signals on the third microphone channel to produce a corrected third microphone signal.

16. The integrated circuit device of claim 15, further comprising:

a beamformer, the corrected second microphone signal and the corrected third microphone signal are input to the beamformer.

17. The integrated circuit device of claim 12, further comprising:

a beamformer, the corrected second microphone signal is input to the beamformer.

18. The integrated circuit device of claim 12, wherein the integrated circuit device is configured into a device worn by a user.

19. An integrated circuit device to automatically balance acoustic channel sensitivity, comprising:

a first signal path, the first signal path is configured to receive and average acoustic signals from a first microphone channel to produce a long-term running average power level of the first microphone channel, exclusive of segments containing desired audio;

a second signal path, the second signal path is configured to receive and average acoustic signals from a second microphone channel to produce a long-term running average power level of the second microphone channel, exclusive of segments containing desired audio;

a first divider, the first signal path is coupled to a first input into the first divider and the second signal path is coupled to a second input into the first divider, the first divider is configured to divide a signal on the first input by a signal on the second input to output an amplitude correction signal; and

a first multiplier, the first multiplier is coupled to the second signal path and to an output of the first divider, the first multiplier is configured to multiply the amplitude correction signal by acoustic signals on the second microphone channel to produce a corrected second microphone signal.

20. The integrated circuit device of claim 19 further comprising:

a first voice band filter, the first voice band filter is part of the first signal path and acoustic signals from the first microphone channel are filtered before the long-term running average power level is calculated; and

a second voice band filter, the second voice band filter is part of the second signal path and acoustic signals from the second microphone channel are filtered before the long-term running average power level is calculated.

21. The integrated circuit device of claim 19, wherein a long-term running average is performed over an interval that can range from a fraction of a second to minutes.

22. The integrated circuit device of claim 19, further comprising:

a third signal path, the third signal path is configured to receive and average acoustic signals from a third microphone channel to produce a long-term running average power level of the third microphone channel, exclusive of segments containing desired audio;

a second divider, the first signal path is coupled to a first input into the second divider and the third signal path is coupled to a second input into the second divider, the second divider is configured to divide a signal on the first input by a signal on the second input to output a second amplitude correction signal; and

a second multiplier, the second multiplier is coupled to the third signal path and to an output of the second divider, the second multiplier is configured to multiply the second amplitude correction signal by acoustic signals on the third microphone channel to produce a corrected third microphone signal.

23. The integrated circuit device of claim 22, further comprising:

a beamformer, the corrected second microphone signal and the corrected third microphone signal are input to the beamformer.

24. The integrated circuit device of claim 19, further comprising:

a beamformer, the corrected second microphone signal is an input to the beamformer.

25. The integrated circuit device of claim 19, wherein the integrated circuit device is configured into a device worn by a user.

26. An integrated circuit device to automatically balance acoustic channel sensitivity, comprising:

means for calculating a long-term power level of a main acoustic signal to obtain an averaged main acoustic signal, wherein segments of the main acoustic signal are excluded from the averaged main acoustic signal using a desired voice activity detection signal;

means for calculating a long-term power level of a reference acoustic signal to obtain an averaged reference acoustic signal, wherein segments of the reference acoustic signal are excluded from the averaged reference acoustic signal using the desired voice activity detection signal; and

means for creating an amplitude correction signal using the averaged main acoustic signal and the averaged reference acoustic signal, wherein the amplitude correction signal is used to adjust either the main acoustic signal or the reference acoustic signal to automatically balance acoustic channel sensitivity.

27. The integrated circuit device of claim 26 further comprising:

means for correcting the main acoustic signal with the amplitude correction signal.

28. The integrated circuit device of claim 26, further comprising:

means for filtering the main acoustic signal with a voice band filter before calculating the long-term power level of the main acoustic signal; and

means for filtering the reference acoustic signal with a voice band filter before calculating the long-term power level of the reference acoustic signal.

29. The integrated circuit device of claim 26, further comprising:

means for calculating a long-term power level of a second reference acoustic signal to obtain an averaged second reference acoustic signal, wherein segments of the second reference acoustic signal are excluded from the averaged second reference acoustic signal using the desired voice activity detection signal; and

means for creating a second amplitude correction signal using the averaged main acoustic signal and the averaged second reference acoustic signal.

30. The integrated circuit device of claim 29, wherein creating the second amplitude correction signal normalizes the averaged main acoustic signal by the averaged second reference acoustic signal and the integrated circuit device further comprising:

means for correcting the second reference acoustic signal with the second amplitude correction signal.